#include "byte_crypto.hpp"
#include "logger.hpp"
#include <openssl/hmac.h>
#include <openssl/ssl.h>
#include <chrono>
#include <random>
#include <cstring>

namespace cpp_streamer
{
uint8_t ByteCrypto::hmac_sha1_buffer[20];
HMAC_CTX* ByteCrypto::hmac_sha1_ctx = nullptr;
const uint32_t ByteCrypto::crc32_table[] =
{
    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
    0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
    0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
    0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
    0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
    0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
    0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
    0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
    0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
    0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
    0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
    0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
    0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
    0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
    0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
    0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
    0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
    0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
    0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
    0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
    0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
    0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};

std::default_random_engine ByteCrypto::random;
bool ByteCrypto::init_ = false;

void ByteCrypto::Init() {
    if (init_) {
        return;
    }
    init_ = true;

    ByteCrypto::hmac_sha1_ctx = HMAC_CTX_new();

    std::memset(hmac_sha1_buffer, 0, sizeof(hmac_sha1_buffer));

    std::chrono::system_clock::duration d = std::chrono::system_clock::now().time_since_epoch();

    std::chrono::milliseconds mil = std::chrono::duration_cast<std::chrono::milliseconds>(d);

    random = std::default_random_engine((uint32_t)(mil.count() & 0xffffffff));
}

void ByteCrypto::DeInit() {
    if (!init_) {
        return;
    }
    init_ = false;

    if (ByteCrypto::hmac_sha1_ctx) {
        HMAC_CTX_free(ByteCrypto::hmac_sha1_ctx);
        ByteCrypto::hmac_sha1_ctx = nullptr;
    }
}

uint32_t ByteCrypto::GetRandomUint(uint32_t min, uint32_t max) {
    std::uniform_int_distribution<uint32_t> dest(min, max);

    return dest(random);
}

uint32_t ByteCrypto::GetCrc32(const uint8_t* data, size_t size) {
    uint32_t crc{ 0xFFFFFFFF };
    const uint8_t* p = data;

    while (size--) {
        crc = ByteCrypto::crc32_table[(crc ^ *p++) & 0xFF] ^ (crc >> 8);
    }

    return crc ^ ~0U;
}

uint8_t* ByteCrypto::GetHmacSha1(const std::string& key, const uint8_t* data, size_t len) {
    int ret = 0;

    ret = HMAC_Init_ex(ByteCrypto::hmac_sha1_ctx, key.c_str(), key.length(), EVP_sha1(), nullptr);
    if (ret != 1) {
        throw CppStreamException("OpenSSL HMAC_Init_ex() failed with key");
    }

    ret = HMAC_Update(ByteCrypto::hmac_sha1_ctx, data, static_cast<int>(len));
    if (ret != 1) {
        throw CppStreamException("OpenSSL HMAC_Init_ex() failed with key");
    }

    uint32_t ret_len = 0;

    ret = HMAC_Final(ByteCrypto::hmac_sha1_ctx, (uint8_t*)ByteCrypto::hmac_sha1_buffer, &ret_len);
    if (ret != 1) {
        throw CppStreamException("OpenSSL HMAC_Final error");
    }
    if (ret_len != 20) {
        throw CppStreamException("OpenSSL HMAC_Final error");
    }

    return ByteCrypto::hmac_sha1_buffer;
}

std::string ByteCrypto::GetRandomString(size_t len) {
    const size_t MAX_LEN = 256;
    char buffer[MAX_LEN];
    static const char chars[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b',
                                'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
                                'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' };
    std::default_random_engine random;

    if (len > MAX_LEN) {
        len = MAX_LEN;
    }
    for (size_t i{ 0 }; i < len; ++i)
    {
        uint32_t rand_number = GetRandomUint(0, sizeof(chars)-1);
        buffer[i] = chars[rand_number];
    }
    return std::string(buffer, len);
}

}
